Spray device for projecting molten particles



Feb. 17, 1948. 1.. M. SIMONSEN SPRAY DEVICE FOR PROJECTING MOLTENPARTICLES Filed Dec. 17, 1943 2 Sheets-Sheet 1 Y NI Euros; L eo/Z5/70/756/7. BY

\KMW mwwwwv N AN mm MN HTTORNEY Feb. 17, 1948. L. M. SIMONSEN 2,436,335

r SPRAY DEVICE FOR PROJECTING 'MOLTEN PARTICLES Fil'ed D80. 17, 1943 2Sheets-Sheet 2 .INVENTOR. Lea M- 5/m0/7sen fla 19% ATTORNEY PatentedFeb. 17, 1948 UNITED STATES PATENT. OFFICE SPRAY DEVICE FOR PIOJECTINGMOLTEN PARTICLE Lee M. Simona. Eugene, Oreg. Application December 1'8,1943, Serial No. 514.63%}

usual melting zone of spray guns or devices of this character iscritical due to the fact that it must provide a high temperaturefor'sumcient time interval to melt the material but not so long that thematerial will be burned by the intense heat generated.

Furthermore, in the spraying of. metallic materials it is desirable todo so in what is known as a reducing atmosphere in order to avoid ex.eessive oxidation of the molten particles, while on the other hand, inthe spraying of certain nonmetallic materials, it is advantageous to do'so in an oxidizing atmosphere. For example, in the spraying of nickelor chromium powders, a high initial melting temperature is necessary anda reducing atmosphere is desirable. -In the spraying of aluminum, zinc,tin, lead. or solder powders. a lower initial temperature is necessaryand a reducing atmosphere is advantageous. In the spraying of glass orceramic glazes, particularly those known as sulphide glazes, a fairlyhigh initial temperature is necessary and an oxidizing atmosphere isdesirable, whereas in the spraying of materials known as plastics, inpowdered form, a low temperature only is required and either anoxidizing, neutral, or reducing atmosphere is used depending upon thecomposition of the plastic utilized.

In the use of conventional devices of this character, when a highinitial melting temperature is required-to melt the powdered materialwithin a given time, there is the danger of overheating the surface uponwhich the molten metal impinges or adheres. This condition is usuallyovercome by altering the distance between the gun nozzle and the baseupon which said molten metal is to impinge, and by increasing the airpressure behind the molten particles, in which event, there is increasedoxidation of the molten material during its trajectory through the flamefrom the gun nozzle to the base surface. Furthermore, during thespraying of powdered glass or glazing material the preheating of thebase surface to a higher 5 (Jlaimo. (cl. 01:42.2)

temperature than that required to initially melt the glass or glaze, isadvantageous to aid in ore ating a satisfactory bond between the glazeor glass and, the base surface and to create a means a of creating auniformly annealed, vitreous coating.

It is an object-of the present invention to provide a spray gun having awide range of adaptabllity and flexibility to suit varying conditionsand materials being applied.

l0 It is a further object of the present invention to provide a spraygun in which, when a higher initial melting temperature is required tomelt the powdered material within a given time, there is not danger ofoverheating the surface upon which ll the molten material impinges.

It is a' further object of the invention to provide a spray apparatuswith which, during the spraying of powdered glass or glazing materials,preheating of the base surface to a higher temper- I. ature and over alarger area than that required to initially melt the glass or glaze, maybe obtained.

It is a further object of the invention to provide a spray apparatus inwhich the powdered ll metal or non-metal or mixture thereof, isintroduced into the flame at a point distant from the gun in such amanner that its melting may take place at a proper time with respect tothe base surface.-

Other objects and advantages of the present invention will appear fromthe following descrip. tion in which the preferred embodiment is setforth in conjunction with the accompanying drawings. ll Referring to thedrawings:

Fig. 1 is a longitudinal sectional view of a spray apparatusincorporating my invention.

Fig. 2 is a. cross-sectional detail taken along the line 22 of Fig. 1.

60, Fig. 3 is a cross-sectional detail taken along {*the line 3-3 of Fi1.

Fig. 4 is a diagrammatic representation of the manner in which thepowdered material is fed into the flame and the manner in which itstrikes the base surface, together with an elevatlonal 60 of the mannerin which it strikes the base surface, together with an elevationalrepresentation of the orifice used.

Fig. 6 is a diagrammatic representation of the manner in which thepowdered material may be I feed into the flame together with arepresentation it is not absolutely essential inasmuch as suitablegasket means may be provided as will hereafter be explained. Body "I! isprovided with a mixing chamber II which divides body I! into twoconcentric shell or wall portions It and 85. Inner shell portion.".isgeneraliy deeper than outer shell I and extends-forwardly along tubeill as shown. Chamber. is closed by an annular rin shaped plate It whichis adapted to fit around shell portion ll andto abut against the forwardface of shell portion. Plate It is provided with orifices H which allc'mpassage of gas from chamber l3.

Tubular member Ilia mounted on body l2 as by means of threads on itsinner surface which. are adapted to cooperate with threads IS on shelll5. It will be seen that when tube II is mountedupon member II, it willcontact plate It and urge it snugly against the forward race of shellit. A plurality of orifices; 2! are provided in member l8 and arearranged preferably in banks oi four,

although that is not an essential part ofthis invention. r

Tubular member 21, which is of greater diamel 4 Thus I have providedannular fiange 24 on the rear end of member l2. A suitably flanged ring8' engages flange N and is secured by means of bolts 31 to a nut 18.This nut together withlock nut ll engages threads ii on member ID toretain tube II in an adjusted position.

As has heretofore been pointed out the slidable connection betweenmembers It and I2 should be as gas-tight as possible. In the eventmachine operations do not permit a thoroughly gas-tight connection to bemaintained, suitable ter than tubular member II, is mounted uponoutershell ll andisconcentric with respect to tubular members II and II.Cooperating threads on members N and I: rovide means whereby.

they may be united or separated at will.

I have provided acircular plate 22 the outside diameter of whichissubstantially equal to the inside diameter of tube 2i. Plate 22 isprovided with two concentric rows of orifices 22 and 24 respectively,and on its rear face. with a circular groove 25 concentric with andlying between said concentric rowsof orifices. Circular groove 25 isgasket or bushings may be utilized in any suitable manner.

Operation of my device may be briefly described as follows: Tube II isconnected to a suitable source of air-under pressure. Suitable means isprovided for feeding the material to be applied, in powdered or granularform, into the air stream, whereby a constant flowof air with dividedsolids homogeneously distributed therein is maintained through tube ll.

Chamber II is likewise connected by means of orifices 82, and 33 to .asuitable source of air or oxygen or a mixture of air or oxygen, and anynatural or artificial fuel gas desired. These gases,

coming in at an angle-of 90 to each other are thoroughly mixed, and thecurved rear surface of chamber I3 assists materially in the mixingoperation and also in projecting the gaseous mixture forward. Thegaseous mixture passes through orifices II in plate It into the chamberbetween members It and H.

mixture willlpass ,through orifices 20 into the A portion of thisorifices 24 because the latter are smaller and be-' cause the pressurewithin the chamber defined by tubes 2! and fl is slightly greater thanthe pressure within the chamber defined by tubes It. and II. Thematerial-laden air is discharged adapted to accommodate 'and locate theadjacent I end of the tubular member ll. Plate 22 is also provided witha centrally located threaded orifice 26.

A nozzle or tip 21 is likewise threaded and is adapted to cooperate withthe threads in centrally disposed orifice 20 whereby the nozzle may beremoved or replaced at will. Tip 21 is bored to-snugly fit about theadjacent end of tube In. without however interfering with adjustment ofthe latter. g

Circular plate 22 is maintained in its position by means ofinteriorannular fiange 2! on member 2|. when member 2! is mounted uponmember H, n e 2| isurged against the outer face of member 2 and plate 22is thereby gripped between fiange 2| on member II and the .forward endof member II, which lies in circular groove from tube ll and nozzle :1into this general flame formed by the intermerging Jets. The patternassumed by the finely divided material being pro- Jected will. dependupon certain factors, including, the distance between the discharge andof tube II and the discharge endof nozzle 21. When these parts arerelatively far apart as shown in 4,.the pattern assumed by the finelydivided material is that of a cone somewhat as illutsrated and thefinely divided material is dispersed accordingly. when the two dischargeorifices are positioned -.relatively close together as shown in P18. 5,the pattern assumedby the discharged material is more limited and thepattern is more compact as the finely-divided material is not so widelydispersed. 1 t

' The reason for the above is that for the retracted position of Figure4 the spread of the discharging jet is determined largely by theconvergent orifice in nozzle 21, whereas for the position of Figure 5.the discharging Jet assumes some of the characteristics-of a jetdischarging from an extended cylindrical orifice. It is well known thatan air or gas jet issuing-from the end of a converging orifice tends tospread over a wider area than a jet issuing from an extended cylindricalorifice (assuming like efiective .fiow areas and pressures) due to thelesser efficiency of the former, to the attendant turbulence of theissuingair stream, and to the tendency of the stream to b slightlycontracted in a region near the diacharge end of the nozzle, beyondwhich region the stream tends to expand.

By employing natural or artificial gases such as propane, butane,acetylene, etc., in combination with air or oxygen, a wide variety offlame temperature is possible. Also by varying the volume of either thenatural or artificial gas in relation to the volume of air 01' oxygenemployed an oxidizing or reducing flame is obtained thus fulfilling oneof the objects previously mentioned herein. By increasing the pressureof both gas and air and assuming the same volume ratio, a longer flameis obtained between the gun nozzle and the base plate on which thematerial is to be deposited. By providing this type of adjustment, arange of from high to low temperature near the nozzle, a sustained rangeof from high to low temperature throughout the flame trajectory, and avariable flame length, each part of which can be an oxidizing, neutral,or reducing atmosphere as desired, are all obtained.

As previously pointed out, by altering the'longitudinal relationshipbetween the discharge ends of tube i0 and nozzle 21, it is possible toobtain a variable length of material cone in either an oxidizing orreducing temperature created by the flame. It should also be noted thatby varying the quantity of powdered material to that of the entralningair, a further adjustment is possible, and in some instances it isnecessary, particularly in consideration of the latent heat of fusion ofvarious metals and their specific gravity. As

an example, a powdered metal with a high latent heat of fusion and ahigh specific gravity will require a low feed rate and a high airpressure in order to permit the suspension of the particles in the air.

with oxygen in order to maintain a melting temperature commensurate withthe latent heatmelting time function, whereas a material hav- 6.'stantiaily rectangular as shown in Fig. 6. the

pattern of the entrained material upon the base to which it is beingapplied will be substantially similar thereto. Generally speaking,therefore,

it may be said that the pattern of the material upon the base willconform generally to the type of orifice in the nozzle 21. Furthermore,it may be pointed out that the size of the pattern upon the base will bea function of the distance be- This condition automatically calls for afuel of high calorific value in combination ing a low latent heat offusionand low specific gravity may be readily floated with low airpressure and readily melted in a flame of natural gas and air.

Further control of the flame is obtained by the type of tip 29 which isemployed. The tip may be either a straight tube acting merely as acontinuation of tube 2|, which is in reality the outer shell of the gunbody, or it maybe flared inwardly or outwardly at varying degreesdepending upon the shape of the flame desired. For example, a, tipflared inwardly as shown in Fig. 1 will yield a concentrated flame bodywhich is necessary particularly in the spraying of high melting pointpowders where a highly localized preheating of the base surface uponwhich the powder is to be applied is advisable and where an excessivelylarge preheated area is not necessary. On the other hand, in the eventone is spraying glass and glazing powders, in which case a lower initialmelting temperature is required and an enlarged preheated area isessential (particularly in the application of spraying glassinconnection with repair work), an outwardly flaring tip would be moresatisfactory.

It has already been pointed out that the relationship between theexhaust orifices of tube ill and nozzle 21 control the path of theentrained material. For example, a nozzle flaring inwardly as shown, theorifice of which is circular, will yield a circular material feed intothe flame the diameter and length of which will be determined by theposition of the two orifices. On the other hand. in the event theorifice is square, or subtween the exhaust nozzle of tube In and nozzle21, that is, the greater the distance between these two orifices, thelarger the pattern, assuming the distance from the base remains thesame.

It has previously been pointed out that I provide a plurality ofconcentric rows or orifices 23 and 24. The purpose of the inner row oforifices is to produce flame as close to nozzle 21 as is feasible. Inthis manner the entrained material is placed directly into the flame anda nearly solid shaft of combustible gases is obtained. Lack of thisparticular inner row of orifices is noticeable in the case where theouter flame ring alone is used in combination with a short material feedcone, in which a satisfactory preheated base surface is obtained coupledwith a short material cone of insufficient length to properly apply thematerial to the base plate unless the gun is held excessively close tothe base plate. It will be recalled that it is desirable to inject theentrained materal into the flame as early as possible, provided,however, that the flame can be controlled. I have provided ample meansof control, for example, the two circular rows or orifices 23 and 2|,theinwardly or outwardl flaring tip 29, a particular form of nozzle 21,and the method of increasing or decreasing gas pressure in chamber I3.

I claim:

1. In a device for spraying molten particles of material upon a surfaceto provide a coating thereon, a nozzle from which said material isdischarged,.a tube communicating with said nozzle and adapted to conveya stream of said material entrained in air, means for creating a zone offlame concentric with said nozzle and extending from said device to saidsurface, and means for controlling the trajectory of said particlesthrough said zone of flame comprising means for controlling the distancebetween the discharge end of said nozzle and the adjacent discharge endof said tube.

2. In a device for projecting particles of material upon a surface toprovide a coating thereon, a tube adapted to receive a stream ofparticles entrained in air, a nozzle communicating with said tube, meansfor creating a zone of flame surrounding the nozzle and extendingbetween said nozzle and said surface, a tip generally surrounding thedischarge end of the nozzle and serving to determine the spread of theflame pat-' centric chambers, orifices serving to connect said chambers,means for supplying a combustible mixture of fuel gas to the outer oneof said chambers, and a member surrounding said nozzle and havingseparate concentric groups of orifices communicating with said chambers,flame jets from said last named orifices serving to form a from thenozzle.

4. In a device for discharging molten particles oi material upon asurface to provide a coating thereon, a nozzle through which saidparticles are discharged, means for creating a zone 01' flame concentricwith said nozzle and extending from said device to said surface. wherebysaid particles will pass through said zone of flame and be meltedthereby, and means for controlling the trajectory of said particlesbetween said nozzle and said surface comprising a tube having adischarge orifice through which said particles pass, the discharge endof said tube being mounted in said'nozzle and longitudinally movablewith respect thereto, and means for longitudinally adjusting said tubewith respect to said nozzle.

5. In a device for spraying molten particles of material upon a surfaceto provide a coating thereon, a, nozzle through. which said material isdischarged, means for creating a zone oi flame concentric with saidnozzle whereby said particles will pass through said zone of time and bemelted thereby, a tube communicating with said nozzle and longitudinallymovable with respect 8 thereto, said tube adapted to carry particlesentrained in gas. means for controlling the distance between thedischarge end of said nozzle and the discharge end of said tube toadjust the pattern of said particles upon said surface for a givenlocation of the device relative to said surface.

LEO M. SIMONSEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,108,998 Schori Feb. 22, 1938788,764 Fitton May 2, 1905 2,125,764 Benoit Aug. 2, 1938 2,137,442Gallon Nov. 22, 1938 1,930,373 Stubenrauch Oct. 10, 1933 988,271 LeeMar. 28, 1911 2,259,215 Scheuser Oct. 14,1941

FOREIGN PATENTS Number Country Date 255,932 Great Britain July 28, 1926

